在C#/ GDI +中从Format8bppIndexed转换为Format24bppRgb

Bitmap originalBitmap = new Bitmap("path/to/image.bmp");
Bitmap newBitmap = new Bitmap(originalBitmap.Width, originalBitmap.Height, PixelFormat.Format24bppRgb);
using (Graphics graphics = Graphics.FromImage(newBitmap))
{
    graphics.DrawImage(originalBitmap, new Rectangle(0, 0, newBitmap.Width, newBitmap.Height));
}
newBitmap.Save("path/to/new/image.bmp");